Interesting enough Obama said the exact same thing about his suit choices.
“You’ll see I wear only gray or blue suits,” [Obama] said. “I’m trying to pare down decisions. I don’t want to make decisions about what I’m eating or wearing. Because I have too many other decisions to make.”(1)
So decision fatigue doesn't need to go hand in hand with super casual.
(1) http://www.vanityfair.com/news/2012/10/michael-lewis-profile...